Pack rat (Neotoma) — woodrat overview and natural history

Physical characteristics

Pack rats are generally smaller than the typical Old World rats and often have long, sometimes bushy tails. They have large eyes and ears relative to body size, whiskers adapted for sensing in low light, and strong incisors for gnawing. Fur color and size vary among species and populations, with coats that help them blend into rocky or desert landscapes.

Habitat and distribution

Members of the genus occupy a range of environments, but many are most abundant in arid and semi‑arid regions. They are commonly associated with rocky outcrops, canyons and scrubland in the deserts and highlands of the western United States and extend into northern Mexico. Different species have specific habitat preferences, from pinyon‑juniper woodlands to desert washes.

Behavior and ecology

Pack rats are primarily nocturnal and build complex nests called middens from plant material, feces, bones, and assorted debris. These middens may be located in rock crevices or underbrush and can persist for long periods. Diets are mainly herbivorous — seeds, leaves, fruit and stems — but some species will consume insects or other small items when available.

• Nest building and midden construction are key behaviors.
• Many pack rats hoard shiny or unusual objects, earning the nickname "trade rat."
• They are prey for owls, coyotes and other predators and serve as seed dispersers.

Human interactions and significance

Pack rats occasionally come into conflict with people when they nest in or near buildings, but they are also valuable to scientists. Fossilized middens preserve plant fragments and small bones, providing insight into past climates and vegetation over thousands of years. Their persistent middens have been used in paleoecology to reconstruct regional environmental change.

Distinctions and notable facts

Although commonly called "rats," pack rats are not closely related to the Old World genus Rattus beyond sharing the broad order of rodents. Their tendency to collect and hoard distinguishes them behaviorally from many other small mammals. For more general taxonomic or natural history information see rodent resources and specific genus references at Neotoma.